
Blai is the middle child of an Alderaanian Bureaucrat (dad) and a Jedi Knight (mom) who is cousin to the Matriarch of Minor House Frayus. His younger sister is training to be a Jedi, and his older brother is a politician in the Lower House who's already married. Jedi might know his mom or little sister, and those with links to Alderaanian politics might know his brother or dad.
He's also a researcher working for the University of Alderaan, so if any others have ties to the university he could have met you there, or at least heard of you.
Also, as a field xenobiologist, he spends most of his time travelling around the Outer Rim and Wild Space. Quite a few of the places are off the main trade routes, and he often needs to carry samples, specimens or other things, preferably without many questions or too much bureaucracy... so freighters don't quite cut it. As a result, he often relies on smugglers or others who often travel around these areas... so if you fit one of these, you may have met him during his travels (as already discussed, that's how he met Riss, with whom he's coming back to Alderaan)